Research & Scholarship

Current Research and Scholarly Interests

High-resolution computed tomography of the thorax,, particularly its application in the setting of acute lung disease in the immunocompromised host; quantitative assessment of abnormalities, using spiral CT; and enhancement characteristics of lung cancers on, CT and MRI

Clinical Trials

Non-small cell lung cancer (NSCLC) is the most deadly cancer in the world. NSCLC annually
causes 150,000 deaths in the US and greater than 1 million worldwide. The standard treatment
for early stage NSCLC is lobectomy with lymphadenectomy. However, many patients are poor
operative candidates or decline surgery. An emerging alternative is Stereotactic Body
Radiation Therapy (SBRT). Mounting evidence from Phase I/II studies demonstrates that SBRT
offers excellent local control. Most SBRT trials focused on small, peripheral tumors in
inoperable patients. Increasingly, clinical trials study SBRT in operable patients, often
with larger, central tumors.
Using clinical staging, a significant proportion of patients harbor occult nodal metastases
when undergoing SBRT to the primary tumor alone. Subgroups of patients carry even higher risk
of nodal metastases. These nodal metastases frequently would be removed by surgical
intervention. However, SBRT, at present, is only directed at the primary tumor, potentially
leading to regional failures in otherwise curable patients. To increase the effectiveness of
SBRT for lung tumors, the next logical step is to explore whether the highest risk areas of
disease spread can be identified and targeted. Regional failure could be reduced and outcome
improved in a significant proportion of patients treated with SBRT if the primary nodal
drainage (PND) were identified, targeted and treated in addition to the primary tumor.
We propose to conduct a study to determine how well water soluble iodinated contrast material
when injected directly into the tumor can be visualized on CT scan and integrated into
radiation therapy treatment planning.

Stanford is currently not accepting patients for this trial.For more information, please contact Laura Gable, (650) 736 - 0798.

Abstract

We propose a novel computational approach for the automated classification of classic versus atypical usual interstitial pneumonia (UIP).Thirty-three patients with UIP were enrolled in this study. They were classified as classic versus atypical UIP by a consensus of 2 thoracic radiologists with more than 15 years of experience using the American Thoracic Society evidence-based guidelines for computed tomography diagnosis of UIP. Two cardiothoracic fellows with 1 year of subspecialty training provided independent readings. The system is based on regional characterization of the morphological tissue properties of lung using volumetric texture analysis of multiple-detector computed tomography images. A simple digital atlas with 36 lung subregions is used to locate texture properties, from which the responses of multidirectional Riesz wavelets are obtained. Machine learning is used to aggregate and to map the regional texture attributes to a simple score that can be used to stratify patients with UIP into classic and atypical subtypes.We compared the predictions on the basis of regional volumetric texture analysis with the ground truth established by expert consensus. The area under the receiver operating characteristic curve of the proposed score was estimated to be 0.81 using a leave-one-patient-out cross-validation, with high specificity for classic UIP. The performance of our automated method was found to be similar to that of the 2 fellows and to the agreement between experienced chest radiologists reported in the literature. However, the errors of our method and the fellows occurred on different cases, which suggests that combining human and computerized evaluations may be synergistic.Our results are encouraging and suggest that an automated system may be useful in routine clinical practice as a diagnostic aid for identifying patients with complex lung disease such as classic UIP, obviating the need for invasive surgical lung biopsy and its associated risks.

Abstract

To investigate the importance of presurgical computed tomography (CT) intensity and texture information from ground-glass opacities (GGO) and solid nodule components for the prediction of adenocarcinoma recurrence.For this study, 101 patients with surgically resected stage I adenocarcinoma were selected. During the follow-up period, 17 patients had disease recurrence with six associated cancer-related deaths. GGO and solid tumor components were delineated on presurgical CT scans by a radiologist. Computational texture models of GGO and solid regions were built using linear combinations of steerable Riesz wavelets learned with linear support vector machines (SVMs). Unlike other traditional texture attributes, the proposed texture models are designed to encode local image scales and directions that are specific to GGO and solid tissue. The responses of the locally steered models were used as texture attributes and compared to the responses of unaligned Riesz wavelets. The texture attributes were combined with CT intensities to predict tumor recurrence and patient hazard according to disease-free survival (DFS) time. Two families of predictive models were compared: LASSO and SVMs, and their survival counterparts: Cox-LASSO and survival SVMs.The best-performing predictive model of patient hazard was associated with a concordance index (C-index) of 0.81 ± 0.02 and was based on the combination of the steered models and CT intensities with survival SVMs. The same feature group and the LASSO model yielded the highest area under the receiver operating characteristic curve (AUC) of 0.8 ± 0.01 for predicting tumor recurrence, although no statistically significant difference was found when compared to using intensity features solely. For all models, the performance was found to be significantly higher when image attributes were based on the solid components solely versus using the entire tumors (p < 3.08 × 10(-5)).This study constitutes a novel perspective on how to interpret imaging information from CT examinations by suggesting that most of the information related to adenocarcinoma aggressiveness is related to the intensity and morphological properties of solid components of the tumor. The prediction of adenocarcinoma relapse was found to have low specificity but very high sensitivity. Our results could be useful in clinical practice to identify patients for which no recurrence is expected with a very high confidence using a presurgical CT scan only. It also provided an accurate estimation of the risk of recurrence after a given duration t from surgical resection (i.e., C-index = 0.81 ± 0.02).

Abstract

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Lung Cancer Screening provide recommendations for selecting individuals for lung cancer screening, and for evaluation and follow-up of nodules found during screening, and are intended to assist with clinical and shared decision-making. These NCCN Guidelines Insights focus on the major updates to the 2015 NCCN Guidelines for Lung Cancer Screening, which include a revision to the recommendation from category 2B to 2A for one of the high-risk groups eligible for lung cancer screening. For low-dose CT of the lung, the recommended slice width was revised in the table on "Low-Dose Computed Tomography Acquisition, Storage, Interpretation, and Nodule Reporting."

Abstract

Professionalism has been described as the "basis of medicine's contract with society." This article reviews the foundational principles of medical professionalism and, more specifically, defines the nature and scope of radiologists' responsibilities to patients. In the face of ongoing changes in the environment of medical practice, maintenance of professionalism is an adaptive challenge that will require successful practitioners to be open to and actively engaged in continuous learning and self-improvement. Imaging 3.0 is a change process developed by the American College of Radiology to help radiologists redefine and reprioritize their professional activities as the discipline transitions from a volume-based to value-based specialty.

Abstract

To identify prognostic imaging biomarkers in non-small cell lung cancer (NSCLC) by means of a radiogenomics strategy that integrates gene expression and medical images in patients for whom survival outcomes are not available by leveraging survival data in public gene expression data sets.A radiogenomics strategy for associating image features with clusters of coexpressed genes (metagenes) was defined. First, a radiogenomics correlation map is created for a pairwise association between image features and metagenes. Next, predictive models of metagenes are built in terms of image features by using sparse linear regression. Similarly, predictive models of image features are built in terms of metagenes. Finally, the prognostic significance of the predicted image features are evaluated in a public gene expression data set with survival outcomes. This radiogenomics strategy was applied to a cohort of 26 patients with NSCLC for whom gene expression and 180 image features from computed tomography (CT) and positron emission tomography (PET)/CT were available.There were 243 statistically significant pairwise correlations between image features and metagenes of NSCLC. Metagenes were predicted in terms of image features with an accuracy of 59%-83%. One hundred fourteen of 180 CT image features and the PET standardized uptake value were predicted in terms of metagenes with an accuracy of 65%-86%. When the predicted image features were mapped to a public gene expression data set with survival outcomes, tumor size, edge shape, and sharpness ranked highest for prognostic significance.This radiogenomics strategy for identifying imaging biomarkers may enable a more rapid evaluation of novel imaging modalities, thereby accelerating their translation to personalized medicine.

Abstract

Haematological patients with neutropenic fever are frequently evaluated with chest computed tomography (CT) to rule out invasive fungal infections (IFI). We retrospectively analysed data from 100 consecutive patients with neutropenic fever and abnormal chest CT from 1998 to 2005 to evaluate their chest CT findings and the yield of diagnostic approaches employed. For their initial CTs, 79% had nodular opacities, with 24.1% associated with the halo sign. Other common CT abnormalities included pleural effusions (48%), ground glass opacities (37%) and consolidation (31%). The CT findings led to a change in antifungal therapy in 54% of the patients. Fifty-six patients received diagnostic procedures, including 46 bronchoscopies, 25 lung biopsies and seven sinus biopsies, with a diagnostic yield for IFI of 12.8%, 35.0% and 83.3%, respectively. In conclusion, chest CT plays an important role in the evaluation of haematological patients with febrile neutropenia and often leads to a change in antimicrobial therapy. Pulmonary nodules are the most common radiological abnormality. Sinus or lung biopsies have a high-diagnostic yield for IFI as compared to bronchoscopy. Patients with IFI may not have sinus/chest symptoms, and thus, clinicians should have a low threshold for performing sinus/chest imaging, and if indicated and safe, a biopsy of the abnormal areas.

Abstract

We describe a case of severe drug-induced interstitial pneumonitis in a woman with idiopathic pulmonary arterial hypertension receiving epoprostenol confirmed by a drug T-cell proliferation assay. Proliferation assays were completed in our patient and in a healthy control. Isolated T cells were incubated with CD3-depleted peripheral blood mononuclear cells and then stimulated to proliferate with (3)H-thymidine in the presence of epoprostenol, other prostanoid analogs, and controls. A significant (p < 0.001) T-cell proliferation response occurred in our patient in the presence of epoprostenol alone. There was a trend towards an increased T-cell response to treprostinil but this was statistically insignificant. There was no significant T-cell response to the diluent alone, normal saline, iloprost, or alprostadil. There was no significant proliferation to any drug in the healthy control. Hence, a drug T-cell proliferation assay confirmed that epoprostenol can rarely incite a profound inflammatory response in the pulmonary interstitium.

Abstract

The diagnostic performance of radiologists using incremental CAD assistance for lung nodule detection on CT and their temporal variation in performance during CAD evaluation was assessed.CAD was applied to 20 chest multidetector-row computed tomography (MDCT) scans containing 190 non-calcified > or =3-mm nodules. After free search, three radiologists independently evaluated a maximum of up to 50 CAD detections/patient. Multiple free-response ROC curves were generated for free search and successive CAD evaluation, by incrementally adding CAD detections one at a time to the radiologists' performance.The sensitivity for free search was 53% (range, 44%-59%) at 1.15 false positives (FP)/patient and increased with CAD to 69% (range, 59-82%) at 1.45 FP/patient. CAD evaluation initially resulted in a sharp rise in sensitivity of 14% with a minimal increase in FP over a time period of 100 s, followed by flattening of the sensitivity increase to only 2%. This transition resulted from a greater prevalence of true positive (TP) versus FP detections at early CAD evaluation and not by a temporal change in readers' performance. The time spent for TP (9.5 s +/- 4.5 s) and false negative (FN) (8.4 s +/- 6.7 s) detections was similar; FP decisions took two- to three-times longer (14.4 s +/- 8.7 s) than true negative (TN) decisions (4.7 s +/- 1.3 s).When CAD output is ordered by CAD score, an initial period of rapid performance improvement slows significantly over time because of non-uniformity in the distribution of TP CAD output and not to a changing reader performance over time.

Abstract

In order to establish a valid surrogate outcome measure, it must be shown that the outcome measure (chest HRCT scores in cystic fibrosis [CF] patients) demonstrates strong statistical association with established endpoints of disease, such as Pseudomonas aeruginosa (Pa) airway acquisition, acute exacerbations, or mortality.We estimated and tested the association between Pa infection status (Pa+ vs. Pa-) and baseline chest HRCT scores in 25 children with mild-to-moderate CF lung disease. For comparison, we estimated the association between Pa status and pulmonary function tests (PFTs), chest X-rays (CXR) scores, and BMI. Pa acquisition was determined from respiratory culture results and systematic review of clinic notes.All subjects had respiratory cultures performed prior to or at baseline with a median of 19 months of retrospective culture observation (SD = 15.7 months, range: 0-52.5 months). The difference between age-adjusted mean total HRCT score for Pa+ versus Pa- was highly significant (P < 0.00001) with a near-perfect separation between scores in Pa+ versus Pa- patients. Similar results were found for several HRCT sub-scores. Among PFTs, only residual volume-to-total lung capacity (RV/TLC) had a significant difference between group means (P = 0.03), but the overlap between groups in RV/TLC measurements was large.CF HRCT scores correlate highly with Pa acquisition, a clinically meaningful measure of progressing CF lung disease. HRCT scores are highly sensitive at predicting Pa acquisition status, while most PFT measures, chest radiograph (CXR) scores, and body mass index are not. These results provide further evidence that HRCT is appropriate for use in patient care and as an outcome measure in clinical trials.

Abstract

The goal was to determine discordance rates between preliminary radiology reports provided by on-call radiology house staff and final reports from attending radiologists on cross-sectional imaging studies requested by emergency department staff after hours.A triplicate carbon copy reporting form was developed to provide permanent records of preliminary radiology reports and to facilitate communication of discrepant results to the emergency department. Data were collected over 21 weeks to determine the number of discordant readings. Patients' medical records were reviewed to show whether discrepancies were significant or insignificant and to assess their impact on subsequent management and patient outcome.The emergency department requested 2830 cross-sectional imaging studies after hours and 2311 (82%) had a copy of the triplicate form stored in radiology archives. Discrepancies between the preliminary and final report were recorded in 47 (2.0%), with 37 (1.6%) considered significant: 14 patients needed no change, 13 needed a minor change, and 10 needed a major change in subsequent management. Ten (0.43%) of the discordant scans were considered insignificant. A random sample of 104 (20%) of the 519 scans without a paper triplicate form was examined. Seventy-one (68%) did have a scanned copy of the triplicate form in the electronic record, with a discrepancy recorded in 3 (4.2%), which was not statistically different from the main cohort (P = .18).Our study suggests a high level of concordance between preliminary reports from on-call radiology house staff and final reports by attending subspecialty radiologists on cross-sectional imaging studies requested by the emergency department.

Abstract

To describe the computed tomography findings of recurrent lymphoma involving the lung.Computed tomography scans of 15 patients with biopsy-proven recurrent lymphoma involving the lung were reviewed. Group mean age of enrolled patients was 38 years (range: 14-68 years). Pathologic specimens were obtained by thoracoscopic or open wedge biopsy (n = 8), transbronchial biopsy (n = 5), and fine needle aspiration (n = 2).Nodules, the most common manifestation, were present in all patients; nodules were greater than 10 in number in 12 (80%) of 15 cases and predominantly 6-10 mm in size in 8 cases (53%). Nodular distribution was bilateral and multilobar except in 2 patients, in whom a solitary pulmonary nodule was found. Lymphadenopathy was the second most common finding; it was seen in 13 (87%) of 15 cases and involved an average of 5 nodal stations.Recurrent lymphoma in the lung most commonly manifests as multiple pulmonary nodules that are typically bilateral and multilobar in distribution.

Abstract

To compare the performance of radiologists and of a computer-aided detection (CAD) algorithm for pulmonary nodule detection on thin-section thoracic computed tomographic (CT) scans.The study was approved by the institutional review board. The requirement of informed consent was waived. Twenty outpatients (age range, 15-91 years; mean, 64 years) were examined with chest CT (multi-detector row scanner, four detector rows, 1.25-mm section thickness, and 0.6-mm interval) for pulmonary nodules. Three radiologists independently analyzed CT scans, recorded the locus of each nodule candidate, and assigned each a confidence score. A CAD algorithm with parameters chosen by using cross validation was applied to the 20 scans. The reference standard was established by two experienced thoracic radiologists in consensus, with blind review of all nodule candidates and free search for additional nodules at a dedicated workstation for three-dimensional image analysis. True-positive (TP) and false-positive (FP) results and confidence levels were used to generate free-response receiver operating characteristic (ROC) plots. Double-reading performance was determined on the basis of TP detections by either reader.The 20 scans showed 195 noncalcified nodules with a diameter of 3 mm or more (reference reading). Area under the alternative free-response ROC curve was 0.54, 0.48, 0.55, and 0.36 for CAD and readers 1-3, respectively. Differences between reader 3 and CAD and between readers 2 and 3 were significant (P < .05); those between CAD and readers 1 and 2 were not significant. Mean sensitivity for individual readings was 50% (range, 41%-60%); double reading resulted in increase to 63% (range, 56%-67%). With CAD used at a threshold allowing only three FP detections per CT scan, mean sensitivity was increased to 76% (range, 73%-78%). CAD complemented individual readers by detecting additional nodules more effectively than did a second reader; CAD-reader weighted kappa values were significantly lower than reader-reader weighted kappa values (Wilcoxon rank sum test, P < .05).With CAD used at a level allowing only three FP detections per CT scan, sensitivity was substantially higher than with conventional double reading.

Abstract

Among patients undergoing heart transplantation, Aspergillus is the opportunistic pathogen with the highest attributable mortality. The median time of onset from transplantation for invasive pulmonary aspergillosis (IPA) was 46 days, but the median time to first positive culture result was 104 days among patients with Aspergillus colonization but no invasive disease. Most patients with IPA presented with fever and cough within the first 90 days of transplantation and with single or multiple pulmonary nodules. None of the heart transplant recipients with either IPA or invasive extrapulmonary aspergillosis (IEPA) had associated neutropenia. Human leukocyte antigen A1 locus was found significantly more frequently among patients colonized with Aspergillus than among patients with IPA (P

Abstract

With the advent of therapies aimed at young patients with cystic fibrosis, who have mildly reduced pulmonary function, the need for improved outcome measures that discriminate treatment effects has become important. Pulmonary function measurements or chest high-resolution computed tomography (HRCT) scores have been separately used to assess interventions. We evaluated these modalities separately and together during a treatment study to develop a more sensitive outcome measure. In a 1-year trial, 25 children randomized either to daily Pulmozyme or to normal saline aerosol were evaluated at randomization and at 3 and 12 months. Outcome variables were pulmonary function test (PFT) results, a global HRCT score, and a composite score incorporating PFTs and HRCT scoring. Regression analyses with generalized estimating equations permitted estimation of the difference in treatment effect between groups over time for each outcome. The largest difference in treatment effects observed at 12 months, measured by the percentage change from baseline, were with the composite total and maximal CT/PFT scores (35.4 and 30.4%), compared with mean forced expiratory flow during the middle half of the FVC (FEF25-75%) (13.0%) and total and maximal global HRCT scores (6.2%, 7.2%). The composite total and maximal CT/PFT scores were the most sensitive outcome measures for discriminating a treatment effect in children with cystic fibrosis with normal or mildly reduced pulmonary function during a 1-year trial of Pulmozyme.

Abstract

The aim of this study was to evaluate the types of swallowing abnormalities that occur in symptomatic patients who have undergone cardiovascular surgery.From 1994 to 2001, 22 patients (17 males and five females; age range, 4-89 years; mean age, 64 years) who had swallowing abnormalities after cardiovascular surgery were referred for a videofluoroscopic swallowing study. Each study was analyzed for functional abnormalities of the tongue, soft palate, epiglottis, hyoid and larynx, pharynx, upper esophageal sphincter, and esophagus. Also, the performance of transesophageal echocardiography, long-term intubation, or both was noted.Swallowing abnormalities were present in 18 patients (81.8%) (range, one to eight functional abnormalities; mean, 3.9 functional abnormalities). The distribution of abnormalities across the functional units statistically significantly deviated (chi(2) = 14.4; df = 6; p = 0.025) from uniform distribution, with abnormalities most commonly involving the hyoid and larynx (13 patients [59.1%]) and the pharynx (10 patients [45.5%]). Aspiration was found in 13 patients (59.1%) (predeglutitive, n = 1; intradeglutitive, n = 4; postdeglutitive, n = 3; and mixed, n = 5). In the 14 patients (63.6%) who underwent transesophageal echocardiography, long-term intubation, or both, we frequently found incomplete tilting of the epiglottis, pharyngeal weakness, and postdeglutitive aspiration.Most patients with swallowing problems after cardiovascular surgery present with multiple abnormalities that most commonly affect the hyoid and larynx and the pharynx and result predominantly in intra- or postdeglutitive aspiration. The performance of transesophageal echocardiography and long-term intubation may influence the types of swallowing abnormalities.

Abstract

Our aim was to evaluate the effectiveness of a commercially available dedicated lung-marker system for localization of pulmonary nodules before video-assisted thoracoscopic surgery.Guidewires were positioned under CT fluoroscopy guidance in 16 patients (11 men, five women; age range, 39-79 years; mean age, 60.4 years). We measured the size of the targeted nodule, its distance to the closest pleural surface, the angle between the introducer needle and the chest wall, and the time for performance of the procedure in each patient. Note was made of any complications after guidewire placement.In the 16 patients, the average nodule size was 6.7 mm (range, 3-12 mm), the average distance to the pleural surface was 10.6 mm (range, 3-22 mm), and the average pleural puncture angle was 59 degrees (range, 25-78 degrees). The marking procedure was completed within an average of 9.5 min (range, 7-15 min). Small pneumothoraces occurred in five (31.3%) of 16 patients. In 15 (93.8%) of 16 patients, thoracoscopic resection of the targeted nodule was successful; in one patient with dyspnea (6.3%), inaccurate localization resulting in an open thoracotomy occurred because an intervening fissure was not visualized. Dislodgement of the guidewire into the pleural space occurred in one patient (6.3%).The dedicated lung-marker system is a fast and effective method for localization of pulmonary nodules before thoracoscopic resection.

Abstract

To determine the frequency, clinical characteristics, and radiologic findings of bronchogenic carcinoma in patients surviving more than 1 month after lung transplantation.The study population was composed of 2,168 consecutive patients at seven lung transplantation centers who survived longer than 1 month after lung transplantation. Medical records, chest radiographs, and computed tomographic (CT) scans obtained at the time of diagnosis and prior images when available were reviewed for various items of information and imaging features.Twenty-four (1%) of the 2,168 patients, all with single-lung transplants, developed cancer in the native lung. Eighteen patients had emphysema, and six had pulmonary fibrosis. The frequencies of cancer in patients with emphysema and fibrosis were 2% (18 of 859 patients) and 4% (six of 147 patients), respectively. Twelve (50%) of their 24 cancers were detected at chest radiography. Fourteen (58%) patients had clinical symptoms. Twenty-one (88%) of the 24 patients had one (n = 11) or more (n = 10) nodules, and nine (38%) had one (n = 8) or more (n = 1) masses visible on CT scans. Nodules and masses were visible on 12 (50%) and seven (29%) of 24 chest radiographs, respectively. Eleven (48%) of 23 cancers for which prior chest radiographs were available were seen retrospectively on prior chest radiographs.Bronchogenic carcinoma develops in the native lung of transplant recipients with emphysema and pulmonary fibrosis with frequencies of 2% and 4%, respectively. The carcinomas most commonly manifest as a pulmonary nodule or mass on chest radiographs, with more nodules seen on CT scans.

Abstract

To perform short echo time MR spectroscopic imaging of the lung parenchyma on normal volunteers.A short echo time projection-reconstruction spectroscopic imaging sequence was implemented on a commercial 1.5T whole body MRI scanner. Images and spectra of the lung parenchyma were obtained from five normal volunteers. Breath-held spectroscopic imaging was also performed.Spectroscopic imaging of short-T2* species allows visualization of different anatomic structures based upon their frequency shifts. A characteristic peak from the parenchyma was seen at three ppm from water frequency.Short echo time MR spectroscopic imaging of the lung parenchyma was demonstrated in normal volunteers. This method may improve proton imaging of the lungs and add specificity to the diagnosis of pulmonary disease.

Abstract

The purpose of this work was to describe the CT and pathologic findings of pulmonary cryptococcosis.CT scans of 11 patients (7 immunocompromised, 4 immunocompetent) with proven pulmonary cryptococcosis were analyzed for number, morphologic characteristics, and distribution of parenchymal abnormalities as well for presence of lymphadenopathy and pleural effusion. Pathology of lung specimens obtained by open biopsy or resection (n = 5) and transbronchial biopsy (n = 1) was reviewed by one dedicated pulmonary pathologist.Pulmonary nodules, either solitary or multiple, were the most common CT finding, present in 10 of 11 patients (91%); associated findings included masses (n = 4), CT halo sign (n = 3), and consolidation (n = 2). On histologic examination, focal areas of ground-glass attenuation surrounding or adjacent to nodules were found to represent airspace collections of macrophages and proteinaceous fluid.Pulmonary cryptococcosis should be considered in the differential diagnosis of solitary or multiple pulmonary nodules (with or without associated CT halo sign), particularly in immunocompromised patients.

Abstract

Noninfectious granulomatous diseases of the lung consist of a diverse group of disorders that logically can be subdivided into those with and without associated vasculitis. This article reviews the epidemiologic, clinical, pathologic, and radiologic features of sarcoidosis, hypersensitivity pneumonitis, berylliosis, and the five entities traditionally classified as pulmonary angiitis and granulomatosis.

Abstract

To evaluate a high-resolution computed tomography (HRCT) scoring system, clinical parameters, and pulmonary function measurements in patients with cystic fibrosis (CF) before and after therapy for a pulmonary exacerbation.Patients (n = 17) were evaluated by spirometer-triggered HRCT imaging, clinical parameters, and pulmonary function tests (PFTs) before and after treatment. HRCT scans were reviewed by 3 radiologists using a modified Bhalla scoring system.Bronchiectasis, bronchial wall thickening, and air trapping were identified in all subjects on initial evaluation. The initial total HRCT score correlated significantly with the Brasfield score (r = -.91, P

Abstract

The purpose of this report is to describe the development and implementation of a faculty mentoring program in radiology designed to promote the career development of junior faculty and enhance communication in the department.The mentoring program was implemented in five stages: organizational readiness, participant recruitment, mentor matching and orientation, implementation, and evaluation. Evaluations were based on Likert scale ratings and qualitative feedback. A retrospective analysis was also conducted of the annual performance reviews of junior faculty in the areas of research, teaching, patient care, and overall performance.An average of 83% (19 of 23) of the junior faculty participated in the pilot phase of the mentoring program. During five rounds of testing, the median rating (1 indicates not important; 10, extremely important) from responding junior faculty was 10 for overall value of individual mentoring meetings; the median rating for the mentors responding was 8.75. Research and academic development were identified as the areas of greatest importance to the faculty. Research and patient care were most improved as assessed by faculty peers during performance reviews. The schedule of semiannual formal mentoring meetings was reported to be optimal.The program was implemented to the satisfaction of junior faculty and mentors, and longitudinal performance suggests positive effects. Issues to be contended with include confidentiality and the time needed for mentoring beyond already saturated schedules. Overall, the authors propose that mentoring programs can be an asset to academic radiology departments and a key factor in maintaining their vitality.

Abstract

The aim of this study was to assess the CT manifestations of bronchocentric granulomatosis.The CT results of five patients with bronchocentric granulomatosis were retrospectively analysed. The patients ranged from 20 to 72 years of age and included three men and two women. The diagnosis of bronchocentric granulomatosis was made at lobectomy (n = 2), open lung biopsy (n = 2), and transbronchial biopsy (n = 1). Only one of the five patients had asthma.The main findings consisted of a spiculated mass lesion (n = 3) or lobar consolidation with associated mild volume loss (n = 2). One of the two patients with consolidation had extensive mucoid impaction. The abnormalities involved predominantly an upper lobe in four patients and a lower lobe in one patient. In the four resected specimens, the macroscopic pathological appearance was consolidation (n = 2) and mass lesion (n = 2). Microscopically, the typical histology of airway-centred necrotizing granulomata was present in all cases. Aspergillus hyphae were identified in two cases. Nocardia sp. was cultured from the biopsy specimen in one case.The CT manifestations of bronchocentric granulomatosis consist of a focal mass or lobar consolidation with atelectasis. These reflect the presence of granuloma formation with or without associated bronchial obstruction.

Abstract

Chronic immunosuppression in organ transplant recipients predisposes to the development of malignant disease. The authors describe their 29-year institutional experience of bronchogenic carcinoma developing after heart and lung transplantation. Seven cases of bronchogenic carcinoma were diagnosed in 1,119 heart and lung transplant recipients. Computed tomography scans and radiographs at time of diagnosis, as well as prior radiographs available in six patients were retrospectively analyzed by two radiologists in consensus. The seven cases involved six heart and one lung transplant recipients. Six patients were smokers with a mean smoking history of 66 pack-years. Mean time interval from transplantation to cancer detection was 25 months. Radiologic findings consisted of a solitary pulmonary nodule (n = 3), mass with satellite nodules (n = 1), and obstructive pneumonitis (n = 1). In the sixth patient, the cancer was not radiographically visible because of obscuration by adjacent fibrosis. On review, radiographic abnormalities were present a mean of 12 months prior to diagnosis in 66% of patients. In the heart or lung transplant population, bronchogenic carcinoma develops in recipients with extensive smoking histories. It presents radiographically as a nodule, mass, or obstructive pneumonitis, and is usually visible on radiographs before the time of diagnosis.

Abstract

Since its clinical introduction in 1991, volumetric computed tomography scanning using spiral or helical scanners has resulted in a revolution for diagnostic imaging. In addition to new applications for computed tomography, such as computed tomographic angiography and the assessment of patients with renal colic, many routine applications such as the detection of lung and liver lesions have substantially improved. Helical computed tomographic technology has improved over the past eight years with faster gantry rotation, more powerful X-ray tubes, and improved interpolation algorithms, but the greatest advance has been the recent introduction of multi detector-row computed tomography scanners. These scanners provide similar scan quality at a speed gain of 3-6 times greater than single detector-row computed tomography scanners. This has a profound impact on the performance of computed tomography angiography, resulting in greater anatomic coverage, lower iodinated contrast doses, and higher spatial resolution scans than single detector-row systems.

Abstract

The purpose of this study was to assess the accuracy of high-resolution CT in the diagnosis of allergic bronchopulmonary aspergillosis in asthmatic patients.The high-resolution CT scans of 44 asthmatic patients with allergic bronchopulmonary aspergillosis and 38 asthmatic patients without allergic bronchopulmonary aspergillosis were analyzed retrospectively and randomly by two independent observers for these features: bronchial wall thickening, bronchiectasis, centrilobular nodules, mucoid impaction, mosaic perfusion, atelectasis, and consolidation. Each observer made a final diagnosis with a stated degree of confidence. The results are expressed as the average number of observations by the two observers.Findings seen more commonly in patients with allergic bronchopulmonary aspergillosis than in patients with asthma alone included bronchiectasis, centrilobular nodules, and mucoid impaction (p < .01, chi-square test). Bronchiectasis was present in 42 (95%) of 44 patients with allergic bronchopulmonary aspergillosis, centrilobular nodules in 41 (93%), and mucoid impaction in 29.5 (67%) (average of two observers). In the asthmatic control group, bronchiectasis was detected in 11 (29%) of 38 patients, centrilobular nodules in 10.5 (28%), and mucoid impaction in 4%. Bronchiectasis was seen in 184 (70%) of 264 lobes of patients with allergic bronchopulmonary aspergillosis compared with 19.5 (9%) of 228 lobes in asthmatic controls (p < .001, chi-square test).In asthmatic patients, bronchiectasis affecting three or more lobes, centrilobular nodules, and mucoid impaction are findings on high-resolution CT that are highly suggestive of allergic bronchopulmonary aspergillosis.

Abstract

Chest radiography is the imaging technique of choice in evaluating patients with suspected pneumonia because of its low radiation dose, low cost, and wide accessibility. In daily practice, radiographs are used to confirm the clinical diagnosis of pneumonia, characterize the extent and severity of disease, search for complications such as empyema, monitor the response to therapy, and examine for possible alternative or additional diagnoses. Although CT scan has no defined role in the routine assessment of patients with either community-acquired or nosocomial pneumonias, its advantages of superior contrast resolution and cross-sectional display can often be helpful in the analysis of complex cases, particularly when radiographic evidence of associated central obstruction, cavitation, lymphadenopathy, or empyema is equivocal. In the immunocompromised patient population, high-resolution CT has been shown to be more sensitive than plain film radiography in the early detection of pulmonary infections.

Abstract

Pulmonary infections are a significant source of morbidity and mortality in the bone marrow transplant population. This pictorial essay reviews the typical time period and imaging findings associated with common pulmonary pathogens that affect bone marrow transplant recipients.

Abstract

To assess the clinical and radiographic findings of pulmonary infections diagnosed by using invasive means.Fifty-nine episodes of pulmonary infection were diagnosed in 52 (7.2%) of a consecutive series of 725 adult bone marrow transplant recipients. Causative organisms, time of diagnoses, radiographic patterns, and mortality rates were reviewed.Cytomegalovirus and Aspergillus species were the two most common pathogens, accounting for 22 and 17 episodes, respectively. During the first 30 days after bone marrow transplantation, fungi caused the majority (nine [82%] of 11 episodes) of pulmonary infections; from days 31 to 100, viruses predominated (21 [62%] of 34 episodes). Recipients of allogeneic transplants had a higher probability of developing Cytomegalovirus pneumonitis than did the recipients of autologous and syngeneic transplants (P < .001). Radiographic findings of Cytomegalovirus pneumonia consisted of parenchymal opacification (90%) and innumerable nodules smaller than 5 mm (29%); in two patients, radiographs were normal. Nodules, masses, or nodules and masses, present in nine (69%) of the 13 patients with Aspergillus infection, were the most common radiographic findings in invasive aspergillosis. Bone marrow transplant recipients with a documented pulmonary infection were found to have a lower event-free survival than recipients without infection (P < .001).Opportunistic pathogens account for the majority of pulmonary infections requiring invasive diagnosis and tend to manifest at predictable times in the course of events following recovery from bone marrow transplantation. Cytomegalovirus, the most common pathogen, causes a spectrum of radiographic findings that includes normal findings. Occurrence of a pulmonary infection is associated with an increased mortality rate.

Abstract

To identify the complications and imaging findings related to lymphangioleiomyomatosis (LAM) after lung transplantation.The authors retrospectively reviewed the clinical histories and imaging studies of 13 patients from five major medical centers who underwent unilateral (n = 8) or bilateral (n = 5) lung transplantation for LAM between 1991 and 1997. Complications related to LAM, both before and after transplantation, were recorded.The following LAM-related complications were found during and after transplantation: excessive pleural adhesions (n = 4), native lung pneumothorax (n = 3), chylous effusion (n = 1), chylous ascites (n = 3), complications from renal angiomyolipomas (n = 4), and recurrent LAM (n = 1). Diagnosis could be made or suggested with computed tomography (CT) in all cases. Four patients (31%) died; one patient died of complications of LAM.Patients who have undergone lung transplantation for LAM have increased morbidity and mortality due to complications related to their underlying disease. These LAM-related complications can be diagnosed or suggested with CT.

Abstract

To review the computed tomographic (CT) findings in pathologically proven chronic pulmonary coccidioidomycosis.The study included 19 pulmonary lesions caused by mycologically and pathologically proven chronic coccidioidomycosis in 18 immunocompetent patients (aged 22 to 75 years, mean 57 years) who had a chest CT scan. Thirteen patients were Canadians who had travelled to an endemic area, and 5 were inhabitants of an endemic area in southern California and Arizona. The CT findings were assessed to determine the type, size, margin, internal architecture and location of parenchymal abnormalities.The CT findings included solitary nodules of 1.0 to 2.0 cm (mean 1.7 cm) in diameter in 17 patients, a focal area of ground-glass attenuation in 1 patient, and focal consolidation in 1 patient. Ten of the nodules had homogeneous attenuation on CT, 2 had central areas of low attenuation, 2 showed cavitation, 2 had foci of calcifications and 1 had bubble lucency. The nodules were located peripherally (in 14 patients) and centrally (in 3 patients). The predominant histologic finding in these nodules was a necrotizing granuloma. Three nodules were surrounded by halos of ground-glass attenuation, which were shown on histologic examination to represent granulomatous inflammation (in 2 cases) and pulmonary hemorrhage due to a pulmonary artery-bronchial fistula (in 1 case). Two nodules had adjacent consolidation, which was due to granulomatous inflammation surrounding a necrotizing granuloma.Necrotizing granulomas in chronic coccidioidomycosis appear as a well-defined nodule on CT, while granulomatous inflammation may appear as areas of ground-glass attenuation or consolidation.

Abstract

To determine if the lower milliampere second setting and shorter acquisition time of subsecond spiral computed tomography (CT) affects the image quality of thoracic CT scans.In 92 consecutive outpatients referred for thoracic CT, spiral CT (120 kV, 292 mA) was performed with 1-second (n = 45) or 0.75-second (n = 47) scanning time. An equal percentage of patients (70%) in each group received intravenous contrast medium. At six mediastinal and six lung zones, degradation due to motion and noise, respectively, were graded independently on a four-point scale by three blinded radiologists. Statistically significant differences were determine with a two-tailed test.Mediastinal image quality was significantly better on 0.75-second scans than on 1-seconds scans (P < .001). Regions with the greatest improvement in image quality were around the aortic root, cardiac ventricles, and aortic arch. Lung image quality was also better on 0.75-second scans than on 1-second scans (P = .04). On 0.75- and 1-second scans, respectively, motion-related artifacts were found to degrade image quality 6.2 and 8.7 times more than noise-related artifacts in the mediastinum and 2.6 and 3.9 times more in the lungs.Subsecond spiral CT is associated with improved clarity and diminished motion artifacts on mediastinal and pulmonary images when compared with 1-second spiral CT.

Abstract

To determine the prevalence of unsuspected pulmonary embolism (PE) on routine thoracic helical computed tomographic (CT) scans and to quantify the improvement in PE detection by using a cine-paging mode on a workstation instead of hard-copy review.Seven hundred eighty-five patients referred for routine contrast medium-enhanced thoracic CT within 9 months were prospectively recruited. Helical CT was performed. Studies were prospectively interpreted by four radiologists. Two radiologists performed routine, undirected, hard-copy consensus review for official interpretation; two of three thoracic radiologists independently performed a dedicated workstation-based search for PE. The presence of PE involving the main, lobar, or segmental pulmonary arteries was assigned a score of 1-5 (1 = definitely negative, 5 = definitely positive) by each independent reviewer. Patients with a score of 4 or 5 underwent lower-extremity ultrasound, ventilation-perfusion scintigraphy, or both, followed by pulmonary CT angiography if the findings were still equivocal.Twelve (1.5%) of the 785 patients had unsuspected PE, with an inpatient prevalence of 5% (eight of 160) and an outpatient prevalence of 0.6% (four of 625). Of the 12 patients with unsuspected PE, 10 (83%) had cancer. Of the 81 inpatients with cancer, seven (9%) had unsuspected PE. A dedicated workstation-based search resulted in detection of PE in three more patients (25%) than did hard-copy interpretation.The prevalence of unsuspected PE was highest among inpatients with cancer. A directed, workstation-based search can improve the PE detection rate over that with hard-copy review.

Abstract

A primary malignant pulmonary hemangiopericytoma was diagnosed in a 45-year-old woman who complained of 10 months of cough and exertional dyspnea. One year after resection of the mass, a metastatic lesion was removed from the contralateral lung. The literature on this unusual pulmonary lesion is reviewed.

Abstract

The objective of this study was to determine if air trapping, as detected on expiratory high-resolution CT (HRCT), is useful as an indicator of bronchiolitis obliterans (BO) in lung transplant recipients. MATERIALS andCorresponding inspiratory and expiratory HRCT images at five different levels and spirometry were obtained in 21 lung transplant recipients. Eleven patients had BO proved by transbronchial biopsy specimens; the remaining 10 patients had no pathologic or functional evidence of airways disease. Two "blinded" observers assessed the inspiratory images for the presence of bronchiectasis and mosaic pattern of lung attenuation, and the expiratory images for presence and extent of air trapping. Statistical comparison of the frequency of HRCT findings between patients with and without BO was performed using Fisher's Exact Test.On inspiratory images, bronchiectasis and mosaic pattern of lung attenuation were present in 4 (36%) and 7 (64%) of 11 patients with BO, and 2 (20%) and 1 (10%) of 10 patients without BO (p>0.05 and p<0.05), respectively. The sensitivity, specificity, and accuracy of bronchiectasis and mosaic pattern for BO were 36%, 80%, and 57%, and 64%, 90%, and 70%, respectively. On expiratory images, air trapping was found in 10 of 11 (91%) patients with BO compared to 2 of 10 (20%) patients without BO (p<0.002). Air trapping was found to have a sensitivity of 91%, specificity of 80%, and accuracy of 86% for BO. Air trapping was identified in one patient with BO who had normal results of baseline spirometric function tests.Air trapping, as detected on expiratory HRCT, was the most sensitive and accurate radiologic indicator of BO in the lung transplant population.

Abstract

Effective utilization of spiral computed tomography (CT) technology in imaging of the thorax requires an understanding of technical parameters that affect image and scan quality. This article discusses how operator-controlled scan parameters can be optimized to achieve diagnostic and cost-effective examinations appropriate for daily clinical practice.

Abstract

This study was to evaluate the accuracy of MR angiography (MRA) using a Gd-DTPA-polyethylene glycol polymer (Gd-DTPA-PEG) with a 3D fast gradient echo (3D fgre) technique in diagnosing pulmonary embolism in a canine model. Pulmonary emboli were created in six mongrel dogs (20-30 kg) by injecting tantalum oxide-doped autologous blood clots into the femoral veins via cutdowns. MRI was performed with a 1.5 T GE Signa imager using a 3D fgre sequence (11.9/2.3/15 degrees) following intravenous injection of 0.06 mmol Gd/kg of Gd-DTPA-PEG. The dogs were euthanized and spiral CT of the lungs were then obtained on the deceased dogs. The MRI images were reviewed independently and receiver-operating-characteristic (ROC) curves were used for statistical analysis using spiral CT results as the gold standard. The pulmonary emboli were well visualized on spiral CT. Out of 108 pulmonary segments in the six dogs, 24 contained emboli >2 mm and 27 contained emboli < or = 2 mm. With unblinded review, MRI detected 79% of emboli >2 mm and only 48% of emboli < or = 2 mm. The blinded review results were significantly worse. Gd-DTPA-PEG enhanced 3D fgre MRI is potentially able to demonstrate pulmonary embolism with fairly high degree of accuracy, but specialized training for the interpretations will be required.

Abstract

Atelectasis is known to change the retractility of the involved part of the lung and the pleural pressure adjacent to it. Consequently, pleural effusions or pneumothoraxes will change their distribution and preferentially migrate toward the site of atelectasis. This alteration will often result in an atypical distribution of pleural liquid or gas. The radiological implications of this phenomenon are discussed herein.

Abstract

Central venous catheters (CVCs) are defined as venous access devices whose tips terminate in the superior or inferior vena cava, regardless of insertion site. CVCs allo reliable, painless, and repeated entry into the venous system and are commonly used for the administration of IV therapy, parenteral nutrition, and blood products as well as for the periodic blood sampling, hemodynamic monitoring, and hemodialysis. Catheter composition and design vary and depend on the duration of intended use and specific functions required. The purpose of this essay is to illustrate commonly used catheters, discuss factors governing catheter selection, and review important catheter-related complications.

Abstract

Until recently paediatric tuberculosis rates were in decline in developed countries, but more recently there has been a significant change in these trends. Tuberculosis in British Columbia (BC) is centralized and all paediatric cases diagnosed between 1979 and 1988 were reviewed. There were 252 notifications during the study period but 50 cases were excluded (31 extrapulmonary cases, 11 with missing records and 8 because of incorrect diagnoses). There were 109 (54%) female patients. The age range was 4 months-15 years (6.4 +/- 4.1 years). 52% were 5 years old or less. 75 (37.1%) were aboriginal Canadians, 61 (30.2%) were Asian, 50 (24.8%) were Caucasian and 16 (8%) were included in miscellaneous or unknown groups. Primary pulmonary disease occurred in 197 (97.5%); the remaining 5 had post-primary disease. A history of close contact was elicited in 158 children (78.2%). All but 8 (4%) had a positive PPD response to 5TU. 40% of children had symptoms, the most frequent being cough (51%) and fever (28.4%). Mycobacteriology was carried out in 169 (83.7%) children. Bacteriologic confirmation was achieved in 45 patients (22.2%). Chest X-rays were reviewed in 186 cases. Lymphadenopathy occurred in 93.5%, with hilar (34%) and combined hilar-paratracheal (26%) being the commonest findings. The majority of patients were treated with isoniazid and rifampin, with a minority receiving streptomycin or pyrazinamide in the initial intensive phase. 14 (6.9%) children had adverse reactions to their drugs but these were rapidly reversed with the withdrawal of the responsible drug. Response to therapy was excellent and there were no deaths.

Abstract

To correlate areas of parenchymal opacification on thin-section computed tomographic (CT) scans with histologic findings in patients with chronic infiltrative lung disease, the CT and histologic findings were evaluated in 29 patients with 11 such diseases. Open-lung biopsy was performed after CT. The area of predominant involvement was classified as air space, interstitium, or a mixture of both. A pathologic score of disease activity was assigned, and the extent of fibrosis was assessed whenever fibrosis was present. Parenchymal opacification on CT scans corresponded to abnormalities that affected mainly the air spaces in three patients (10%), the interstitium in 13 patients (45%), or both to a similar degree in 13 patients (45%). In 25 of 29 patients (86%), parenchymal opacification was associated with potentially treatable or reversible disease. Abnormalities considered irreversible were seen in three patients with end-stage fibrosis and one patient with talcosis. Parenchymal opacification on thin-section CT scans is a nonspecific finding in diseases that affect the air spaces, interstitium, or both but usually indicates potentially treatable or reversible disease.

Abstract

The aim of the study was to review the radiologic features of primary tuberculosis in childhood and to determine whether differences in patterns of disease occur among age and ethnic groups. Chest radiographs of 191 children with pediatric primary tuberculosis were reviewed by two observers. Lymphadenopathy, present in 92% of cases, was the most common abnormality identified on the initial chest radiograph and typically involved the hilar and paratracheal regions. Parenchymal abnormalities, identified in 70% of cases, occurred more commonly in the right lung (P less than .001). Children 0-3 years of age had a higher prevalence of lymphadenopathy (P less than .01) and a lower prevalence of parenchymal abnormalities (P less than .001) than older children. A lower prevalence of lymphadenopathy was found in whites than in nonwhites (P less than .02). The radiologic abnormalities often progressed in the initial follow-up. Lymphadenopathy, with or without concomitant parenchymal abnormality, is the radiologic hallmark of primary tuberculosis in childhood. However, distinct age-related and racial differences in presenting patterns of disease exist and should be recognized.

Abstract

We compared the accuracies of high-resolution CT (HRCT) and conventional CT in determining the specific diagnoses in 75 consecutive patients with chronic diffuse infiltrative lung disease. Without knowledge of clinical or pathologic data, two reviewers independently assessed three separate sets of CT scans in random order: three HRCT scans, three 10-mm collimation CT scans obtained at the same levels as the HRCT scans, and a complete conventional CT scan. The HRCT scans were obtained at the level of the aortic arch, tracheal carina, and 1 cm above the right hemidiaphragm by using 1.5-mm collimation and a high spatial resolution algorithm. Observers gave the most likely diagnosis along with their degree of diagnostic confidence. The correct diagnosis, irrespective of confidence level, was reached with 71% of the HRCT scans and with 72% of both the corresponding 10-mm and complete conventional CT scans. Confidence level 1 (definite) was reached with 49% of HRCT scans, 31% of corresponding 10-mm scans, and 43% of complete conventional CT examinations; the correct diagnosis was made in 92%, 96%, and 94% of those examinations, respectively. In none of the patients were findings on the limited HRCT scan normal when findings on the conventional CT scan were abnormal. We conclude that in most patients with chronic infiltrative lung disease a specific diagnosis can be made by obtaining a limited number of HRCT scans.

Abstract

The CT features of benign and malignant pleural diseases have been described. However, the accuracy of these features in the differential diagnosis of diffuse pleural disease has not been assessed before. Without knowledge of clinical or pathologic data, we reviewed the CT findings in 74 consecutive patients with proved diffuse pleural disease (39 malignant and 35 benign). The patients included 53 men and 21 women 23-78 years old. Features that were helpful in distinguishing malignant from benign pleural disease were (1) circumferential pleural thickening, (2) nodular pleural thickening, (3) parietal pleural thickening greater than 1 cm, and (4) mediastinal pleural involvement. The specificities of these findings were 100%, 94%, 94%, and 88%, respectively. The sensitivities were 41%, 51%, 36%, and 56%, respectively. Twenty-eight of 39 malignant cases (sensitivity, 72%; specificity, 83%) were identified correctly by the presence of one or more of these criteria. Malignant mesothelioma (n = 11) could not be reliably differentiated from pleural metastases (n = 24). We conclude that CT is helpful in the differential diagnosis of diffuse pleural disease, particularly in differentiation of malignant from benign conditions.